Wood panel laminates and composite wood panel products, such as, for example, plywood, laminated veneer lumber (LVL), oriented strand board (OSB), and particle board (PB), are widely used in the building and construction process and in the fabrication of a wide variety of building components and structures, including furniture, cabinetry, and boxes, large and small. These laminate and composite products offer improved strength, unique dimensional or fabrication characteristics, and greater availability and versatility compared to natural solid wood or lumber, while costing significantly less than natural solid wood and requiring less labor to prepare and make ready for use by consumers.
One significant drawback to the use of many of these manufactured wood panel products, however, is that they have a rough, industrial appearance and are generally less cosmetically attractive than solid wood. Because these products are usually mass produced from veneers of wood, strands and flakes of assorted wood fiber, or chips and particles of wood randomly bonded together, the face and edge surfaces of the products are usually coarse, grainy, rough, and include imperfections such as splits, gaps, stained wood, discolored resin and knots, which usually detract from the cosmetic appearance of the product, and limit functional uses and fabrication of derivative products.
Another disadvantage is that the rough gaps and coarse, flashy raised grain of many types of wood laminate and composite panels products show or "telegraph" through many types of conventional cosmetic appearance improving or protective coatings or overlays, such as thin veneer, paper and vinyl sheet laminating layers and paint. One common way to try to improve the surface appearance of laminate panel wood products, especially veneer and laminated products, such as plywood and LVL, is to use a procedure known as "plug and touch sanding." In this procedure, each surface layer of veneer is inspected for large knots or imperfections. Prior to laminating, an operator removes these imperfections with a hydraulic punch, cutting out the imperfection in a preselected shape. The holes thus formed are filled with wooden plugs which have been pre-cut to the same shape as the hole. After laminating, the surface layers of the resulting wood panel are inspected again, and rough spots, and the plugs themselves, are sanded to help smooth the surface of the product. Any remaining defects in the surfaces of the laminated product can then be removed by using a router to create a depression where the defect was, and then adding a putty or patching compound by hand prior to a final sanding of a panel. Each of these procedures is labor intensive, time consuming and expensive. The resulting product, while improved, is still not suitable for many applications for which an attractive appearance or a smooth surface is desired.
Wood products manufactured in the above manner are sometimes used as, for example, concrete form boards for poured concrete. Surface imperfections are telegraphed onto the surface of the finished concrete. Typically, these concrete form products must additionally undergo a process to apply a clear, defect-free hardwood overlay to the substrate to prevent substrate defects from telegraphing. Normally, a sheet of high quality hardwood veneer which is free of large imperfections is laminated to a very thin, smooth, water-resistant, resin impregnated paper called a Medium Density Overlay (MDO) and attached using a press in the normal laminate pressing process, or is glued onto the laminated wood product in a roll coating process after the laminate pressing is complete. Thus, the combination of a hardwood and MDO overlay provides a smooth, clean surface by which the MDO contacts the wet cement so that no imperfections remain in the surface of the wood laminate product and, thus, no defects are be telegraphed to the surface of the finished concrete. This process, however, is labor and material intensive and significantly increases the cost of concrete form board due to the expense of the hardwood overlay and the MDO resin paper overlay.
In many other applications, conventional wood products suffer from the additional disadvantage that they are water permeable, which can result in staining, swelling, dimensional distortion, deterioration or even disintegration.
In view of the above, it should be appreciated that there is a need for a method and product that improves the performance and appearance of wood laminate and composite wood products that is inexpensive, labor efficient, and results in a continuous homogenous smooth surface that is substantially free of imperfections, is suitable for refabrication, painting or other cosmetic enhancement, and does not materially reduce the structural strength or dimensional stability of the product, but does increase resistance to water damage. The present invention satisfies these and other needs and provides further related advantages.